TW202008136A - Touch display control circuit, control method and electronic device - Google Patents

Abstract

The present disclosure provides a touch display control circuit, a control method and an electronic device. The touch display control circuit is configured to drive a STN-LCD, a TN-LCD or a CSTN-LCD, and includes a display drive circuit and a touch control detection circuit. The display drive circuit includes a signal transmission trace, multigroup of signal selection circuits and a reference voltage generation circuit; the signal transmission trace is configured to transmit a grid signal and a public signal, the signal selection circuit gates a preset control voltage based on a display control timing sequence or a display touch control timing sequence, the reference voltage generation circuit provides the preset control voltage. The touch control circuit is connected with the signal selection signal, and performs touch detection based on the display touch control timing sequence. Therefore, the touch display control circuit provided by the technical solution can make the LCD screen, such as the STN-LCD, the TN-LCD and the CSTN-LCD, has a touch function without changing the structure of the original liquid crystal screen.

Description

Touch display control circuit, control method and electronic device

The present invention relates to the field of semiconductor technology, and more specifically, to a touch display control circuit, control method, and electronic equipment.

With the continuous development of technology, the LCD screen with touch function has become a major development trend of electronic devices. At present, capacitive touch technology is widely used on TFT-LCD liquid crystal screens.

STN-LCD, TN-LCD, CSTN-LCD and other LCD screens have lower brightness and dynamic response speed than TFT-LCD liquid crystal screens, but STN-LCD and other liquid crystal screens are still widely used in electronic equipment due to their low cost. If you choose to attach a touch screen to such a low-cost LCD screen, it will result in poor display effect of the integrated LCD screen and increase costs. Therefore, the current LCD screens are only used for display and do not have touch functions.

Based on this, how to provide a touch display circuit that can enable the STN-LCD, TN-LCD, and CSTN-LCD liquid crystal screens to have a touch function without changing the structure of the original liquid crystal screen is a breakthrough for those skilled in the art A technical problem.

In view of this, the present invention provides a touch display control circuit, control method and electronic device, which can make the STN-LCD, TN-LCD and CSTN-LCD liquid crystal screens have touch without changing the structure of the original liquid crystal screen Control function.

To achieve the above objectives, the present invention provides the following technical solutions:

A touch display control circuit is used to drive a liquid crystal screen. The touch display control circuit includes:

A display driving circuit including a signal transmission trace, a signal selection circuit, and a reference voltage generation circuit. The signal transmission trace is used to transmit gate signals and common signals. The signal selection circuit is based on display control timing or Displaying the touch control timing to gate the preset control voltage, the reference voltage generating circuit is connected to the signal selection circuit, and is used to provide the preset control voltage.

The touch detection circuit is connected to the signal selection circuit, and performs touch detection based on the display touch control timing.

Optionally, the signal selection circuit includes: a gate signal selection subcircuit, connected to the reference voltage generation circuit, strobes a target gate voltage based on the display control timing, and transmits the target gate voltage to A gate trace in the signal transmission trace; a common electrode signal selection sub-circuit, connected to the reference voltage generating circuit, strobes a target common voltage based on the display control timing or the display touch control timing, and Transmitting the target common voltage to a common wiring in the signal transmission wiring.

Optionally, there are multiple touch detection circuits, each of the common traces is connected to one of the common electrode signal selection sub-circuits, and each of the common electrode signal selection sub-circuits is connected to any one of the touch The detection circuit is connected.

Optionally, each of the common traces is connected to one of the common electrode signal selection sub-circuits, and a plurality of the common electrode signal selection sub-circuits are all connected to the same touch detection circuit.

Optionally, the signal selection circuit includes a plurality of switches, and the control end of each switch is connected to the display control timing or the display touch control timing, and gates a preset control voltage to the signal transmission line.

Optionally, there are multiple touch detection circuits, each of the common traces is connected to one of the signal selection circuits, and each of the signal selection circuits is connected to any one of the touch detection circuits.

Optionally, each of the common traces is connected to one of the signal selection circuits, and a plurality of the signal selection circuits are connected to the same touch detection circuit.

Optionally, the touch detection circuit includes an amplifier and multiple switches.

The amplifier is used to detect the change value of the self-capacitance of the common electrode and output a voltage signal corresponding to the change value of the self-capacitance.

A control method is applied to the above-mentioned touch display control circuit. The control method includes: in a display timing section, based on the display control timing, controlling the display driving circuit to be in an on state and controlling the touch detection circuit to be in Isolation state, and the preset control voltage is gated so that the display driving circuit outputs the preset control voltage to the signal transmission trace; in the display touch timing section, based on the display touch control timing, the control is controlled The touch detection circuit performs touch detection.

Optionally, the display touch timing segment includes a first stage and a second stage.

In the first stage, the display driving circuit is in an on state, and the touch detection circuit is in an isolated and self-correcting state.

In the second stage, the touch detection circuit is in a detection state.

Optionally, the display control timing and the display touch control timing are executed according to a preset rule; the preset rule includes: performing the display control timing m times and n times the display touch control timing alternately for consecutive executions ; Where m is an integer greater than or equal to 0; and n is an integer greater than or equal to 1.

An electronic device includes an electronic device body and any one of the aforementioned touch display control circuits.

Compared with the prior art, the technical solution provided by the present invention has the following advantages:

The invention provides a touch display control circuit for driving STN-LCD, TN-LCD and CSTN-LCD liquid crystal screens, including a display driving circuit and a touch detection circuit. Among them, the display driving circuit includes a signal transmission trace, multiple sets of signal selection circuits and a reference voltage generation circuit. The signal transmission trace is used to transmit gate signals and common signals. The signal selection circuit selects based on display control timing or display touch control timing. With the preset control voltage, the reference voltage generating circuit provides the preset control voltage. The touch detection circuit is connected to the signal selection circuit, and performs touch detection based on the display touch control timing. It can be seen that the touch display control circuit provided by this solution can enable the STN-LCD, TN-LCD, CSTN-LCD and other liquid crystal screens to have a touch function without changing the structure of the original liquid crystal screen.

The technical solutions in the embodiments of the present invention will be described clearly and completely in combination with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those with ordinary knowledge in the technical field without making creative work fall within the protection scope of the present invention.

According to the prior art, some existing liquid crystal screens (such as STN-LCD, TN-LCD, CSTN-LCD, etc.) fail to realize the touch function, and the inventors consider that these liquid crystal screens are usually used in low-cost electronic devices. In addition, in the prior art, the touch screen modules (including the touch screen and the touch chip) are attached to these liquid crystal screens, or such liquid crystal screens may have a touch function. However, the method of sticking the screen will cause the display effect of the original LCD screen to decrease and the cost to increase significantly, which is contrary to the low-cost use concept.

Based on this, taking the STN-LCD liquid crystal screen as an example, the inventor combined the display principle of the current STN-LCD liquid crystal screen, and realized the touch function of the STN-LCD liquid crystal screen by not adding a touch screen. As shown in Figure 1, for STN-LCD liquid crystal screens, usually driven by a waveform similar to the capacitive touch screen (CTP) drive waveform, of which, the odd timing (ODD FRAME) and even timing (EVEN FRAME) are selected The mutually symmetrical waveforms can further eliminate the adverse effects of the DC component on the liquid crystal.

Specifically, taking the waveform whose control voltage is 6level as an example, when each common voltage is in an inactive state, the current common voltage is set to the second preset voltage V1, and when the common voltage is in the activated state, the current The common voltage is the sixth preset voltage V5. Then, the common voltage transmitted by different common traces changes the signal according to a certain time interval.

In this embodiment, the gate voltage is set as the second preset voltage V1 as intermediate data, the third preset voltage V2 as the high voltage of the gate voltage, and the first preset voltage V0 as the low voltage of the gate voltage .

The waveforms of the common voltage and the gate voltage in FIG. 1 are drawn together at the same time, and the waveform curve shown in FIG. 2 is shown. The thick black line in the figure is the waveform of the common voltage, and the diamond structure is the gate voltage. The waveform range, that is, the gate voltage is the third preset voltage V2 or the first preset voltage V0.

Based on the above embodiment, the driving circuit shown in FIG. 3 can be used to select the common voltage. For example, when the switch 31 is closed, the common voltage is the sixth preset voltage V5, and when the switch 33 is closed, The common voltage is the second preset voltage V1.

Specifically, each common trace COM(i) corresponds to a switch group 111(i), where i is a positive integer greater than or equal to 1. Correspondingly, each gate trace SEG (j) corresponds to a switch group 121 (j), where j is also a positive integer greater than or equal to 1, and then control the switch group 111 (i) in the sequence 112 (i) The on and off states of the switch control the on and off states of the switches in the switch group 121 (j) through the sequence 122 (j), and then the corresponding common voltage and gate voltage are output.

Schematically, referring to FIG. 3, the switch group 111(i) includes a switch 31, a switch 32, a switch 33, and a switch 34. Specifically, one end of the switch 31 is connected to the sixth preset voltage V5, and one end of the switch 32 is connected to the fifth The preset voltage V4 is connected, one end of the switch 33 is connected to the second preset voltage V1, one end of the switch 34 is connected to the first preset voltage V0, the other end of the switch 31, the other end of the switch 32, the other end of the switch 33 and The other end of the switch 34 is connected to the common trace COM(i).

The switch group 121(j) includes a switch 35, a switch 36, a switch 37, and a switch 38. Specifically, one end of the switch 35 is connected to the sixth preset voltage V5, one end of the switch 36 is connected to the fourth preset voltage V3, and the switch 37 Is connected to the third preset voltage V2, one end of the switch 38 is connected to the first preset voltage V0, the other end of the switch 35, the other end of the switch 36, the other end of the switch 37 and the other end of the switch 38 are all connected to the gate Connect SEG(j) to the pole trace.

Among them, FIG. 3 also provides a reference voltage generating circuit for generating a preset voltage. For example, a resistor divider circuit formed by resistor 11, resistor 12, resistor 13, resistor 14, and resistor 15 can obtain the required voltage value, and then through operational amplifier 21, operational amplifier 22, operational amplifier 23, operational amplifier 24 can provide V0, V1, V2, V3, V4, V5 voltage.

In addition, it should be noted that in the embodiment of the present invention, the circuit shown by 101 is located inside the chip, and the signal transmission trace 500 shown by 102 is located outside the chip (on the LCD screen); that is, the signal transmission shown by 102 The traces are connected to the pins of the chip, and the pins of the chip extend to the liquid crystal screen, and a trace pattern shown by 102 is formed on the liquid crystal screen. It can be understood that, in this embodiment, the signal transmission wiring shown in section 102 and the display driving circuit 501 are combined for description to facilitate explanation.

On this basis, the inventor combined the driving principle of the touch circuit 200 as shown in FIG. 4, when the first timing, the control switch 61 and the switch 62 are both open, and the control switch 64 is closed. Among them, one end of the switch 64 is connected to the second preset voltage V1, the other end of the switch 64 is connected to the in-phase input 41 of the amplifier 50, one end of the switch 60 is connected to the inverting input of the amplifier 50, and the other end of the switch 60 is connected to the touch The output of the control circuit is connected.

At this time, the switch 60 is closed, the amplifier 50 performs an automatic clear operation, the amount of charge Q(C51) on the capacitor 51 = 0, and the output voltage Vo of the touch circuit is V1.

The switch 71 and the switch 73 are closed, the switch 72 is opened, the upper end of the capacitor 70 is connected to the voltage VDD, and the lower end is grounded to store the preset charge.

At the same time, the common wiring COM is connected to the sixth preset voltage V5 to perform a precharge operation. It can be seen that the sum of the charge amounts of the three parts of the circuit in FIG. 4 is Q1=0+C70*VDD+Cself*V5, where Cself is the self-capacitance of the common electrode.

At the second timing, the control switch 61 and the switch 62 are closed.

At this time, the switch 60 is turned off, and the amplifier 50 performs a detection action.

Switch 71 and switch 73 are open, switch 72 is closed, and the lower end of capacitor 70 is connected to voltage VDD.

At this time, due to the virtual ground effect of the amplifier 50, the potential of COM will be maintained at the second preset voltage V1.

It can be seen that the sum of the charge amounts of the three parts of the circuit in Figure 4 is Q2=C51*(V1-Vo)+C70*(V1-VDD)+Cself*V1.

Since Q2=Q1, the output voltage of the touch circuit Vo=V1+C70/C51*(V1-2*VDD)+Cself/C51*(V1-V5). Cself is the original self-capacitance. When a finger touches it, it will change the capacitance Cfinger. Cself will become Cself’=Cself+Cfinger, which will not be repeated here.

Therefore, based on the above circuit, the detection of the touch event can be realized by detecting the change of the voltage at the output terminal of the amplifier.

The inventor integrates the above touch circuit and driving circuit. As shown in FIG. 5, an embodiment of the present invention provides a touch display control circuit. The touch display circuit is applied to drive a liquid crystal screen. The touch display control The circuit includes: a display driving circuit 501 and a touch detection circuit 502.

The display driving circuit 501 includes a signal transmission trace 500, a signal selection circuit (504 and 121(j)), and a reference voltage generation circuit 503. The signal transmission trace 500 is used to transmit gate signals and public signals. The signal selection circuit (504 and 121(j)) gates a preset control voltage based on the display control timing 122(j) or the display touch control timing 132(i), the reference voltage generating circuit 503 and the signal selection The circuits (504 and 121(j)) are connected to provide the preset control voltage. The touch detection circuit 502 is connected to the signal selection circuit 504, and performs touch detection based on the display touch control timing.

It can be seen that the touch display control circuit provided by the solution combines the display driving circuit and the touch detection circuit, and can make the original liquid crystal screen have a touch function without changing the structure of the original liquid crystal screen.

Specifically, there are multiple implementations of the signal selection circuit provided in this embodiment. Please continue to refer to FIG. 5. The signal selection circuit provided in this embodiment includes:

The gate signal selection sub-circuit 121(j) is connected to the reference voltage generating circuit 503, gates a target gate voltage based on the display control timing 122(j), and transmits the target gate voltage to the The gate trace SEG in the signal transmission trace.

The common electrode signal selection sub-circuit 504 is connected to the reference voltage generating circuit 503, gates a target common voltage based on the display control timing 122(j) or display touch control timing 132(i), and connects the target common The voltage is transmitted to the common wiring COM in the signal transmission wiring 500.

It is worth mentioning that, as shown in FIG. 5, the touch display circuit provided in this embodiment includes multiple touch detection circuits 502. Specifically, each of the common traces COM(i) and one of the The common electrode signal selection sub-circuit 504 is connected, and each of the common electrode signal selection sub-circuits 504 is connected to one of the touch detection circuits 502.

That is, in this embodiment, the number of the common electrode signal selection sub-circuit 504 is the same as the number of the touch detection circuit 502, and the common electrode signal selection sub-circuit 504 and the touch detection circuit 502 together constitute the first circuit 131(i) .

Based on the above embodiments, the embodiments of the present invention also provide a specific implementation structure of the common electrode signal selection sub-circuit 504 and the gate signal selection sub-circuit 121(j). The common electrode signal selection sub-circuit 504 includes A switch 31, a second switch 32, a third switch 33 and a fourth switch 34, the gate signal selection sub-circuit 121(j) includes a fifth switch 35, a sixth switch 36, a seventh switch 37 and an eighth switch 38.

Specifically, the first end of the first switch 31, the first end of the second switch 32, the first end of the third switch 33, and the first end of the fourth switch 34 are all the same The common trace COM(i) is connected.

The second end of the first switch 31, the second end of the second switch 32, the second end of the third switch 33, and the second end of the fourth switch 34 are in turn It is assumed that the voltage V5, the fifth preset voltage V4, the second preset voltage V1 and the first preset voltage V0 are connected.

The control terminal of the first switch 31, the control terminal of the second switch 32, the control terminal of the third switch 33, and the control terminal of the fourth switch 34 are all connected to the display control timing 122(j) Or display touch control timing 132 (i).

The first end of the fifth switch 35, the first end of the sixth switch 36, the first end of the seventh switch 37, and the first end of the eighth switch 38 are all the same as the gate Connect SEG(j) to the pole trace.

The second terminal of the fifth switch 35, the second terminal of the sixth switch 36, the second terminal of the seventh switch 37, and the second terminal of the eighth switch 38 are in turn It is assumed that the voltage V5, the fourth preset voltage V3, the third preset voltage V2 and the first preset voltage V0 are connected.

The control terminal of the fifth switch, the control terminal of the sixth switch, the control terminal of the seventh switch, and the control terminal of the eighth switch are all connected to the display control timing 122 (j).

It should be noted that, in this embodiment, there are multiple touch detection circuits. In addition, there may be only one touch detection circuit, such as the display driving circuit 600 shown in FIG. 6, each of the common traces COM(i) is connected to one of the common electrode signal selection sub-circuits 601, and a plurality of the The common electrode signal selection sub-circuit 601 is connected to the same touch detection circuit 602. This can reduce the number of touch detection circuits 602 used, so that the overall size of the entire display panel can be reduced.

Specifically, the display driving circuit 600 shown in FIG. 6 further provides a specific implementation structure of a common electrode signal selection sub-circuit 601 and a gate signal selection sub-circuit 603, wherein the common electrode signal selection sub-circuit 601 includes a ninth switch 31' , A tenth switch 32', an eleventh switch 33', a twelfth switch 34' and a thirteenth switch 35', the gate signal selection sub-circuit 603 includes a fourteenth switch 36' and a fifteenth switch 37 ', the sixteenth switch 38' and the seventeenth switch 39'.

Specifically, the first end of the ninth switch 31', the first end of the tenth switch 32', the first end of the eleventh switch 33', the first end of the twelfth switch 34' One end and the first end of the thirteenth switch 35' are both connected to the same common trace COM(i).

The second end of the ninth switch 31', the second end of the tenth switch 32', the second end of the eleventh switch 33', and the second end of the twelfth switch 34' It is connected to the sixth preset voltage V5, the fifth preset voltage V4, the second preset voltage V1 and the first preset voltage V0.

The control terminal of the ninth switch 31', the control terminal of the tenth switch 32', the control terminal of the eleventh switch 33', and the control terminal of the twelfth switch 34' are all connected to the display Control timing or display touch control timing.

The second terminal of the thirteenth switch 35' is connected to the touch detection circuit 602.

The first end of the fourteenth switch 36', the first end of the fifteenth switch 37', the first end of the sixteenth switch 38', and the first end of the seventeenth switch 39' are all the same as the gate Connect SEG(j) to the pole trace.

The second terminal of the fourteenth switch 36', the second terminal of the fifteenth switch 37', the second terminal of the sixteenth switch 38', and the second terminal of the seventeenth switch 39' are in turn It is assumed that the voltage V5, the fourth preset voltage V3, the third preset voltage V2, and the first preset voltage V0 are connected.

The control terminal of the fourteenth switch 36', the control terminal of the fifteenth switch 37', the control terminal of the sixteenth switch 38' and the control terminal of the seventeenth switch 39' are all connected to the display control timing.

Based on the above embodiments, the embodiments of the present invention also provide a specific implementation structure of a signal selection circuit. As shown in FIG. 7, the signal selection circuit 151(i) includes multiple switches, each of which has a The control terminal can be connected to the display control timing or the display touch control timing, and gate the preset control voltage to the signal transmission trace 500.

Specifically, the signal selection circuit includes: an eighteenth switch 311, a nineteenth switch 321, a twentieth switch 331, a twenty-first switch 341, a twenty-second switch 351, a twenty-third switch 361, and a twentieth Four switches 371.

Wherein, the first end of the eighteenth switch 311, the first end of the nineteenth switch 321, the first end of the twentieth switch 331, the first end of the twenty-first switch 341, the twenty-second switch The first end of 351, the first end of the twenty-third switch 361, and the first end of the twenty-fourth switch 371 are all connected to the same common trace COM(i) or the same gate trace SEG (j ) Connected.

The second terminal of the eighteenth switch 311, the second terminal of the nineteenth switch 321, the second terminal of the twentieth switch 331, the second terminal of the twenty-first switch 341, the second terminal of the twenty-second switch 351 Terminal, the second terminal of the twenty-third switch 361, and the second terminal of the twenty-fourth switch 371 in sequence with the sixth preset voltage V5, the fifth preset voltage V4, and the fourth preset voltage V3, the third preset voltage V2, the second preset voltage V1 and the first preset voltage V0 are connected.

The control terminal of the eighteenth switch 311, the control terminal of the nineteenth switch 321, the control terminal of the twentieth switch 331, the control terminal of the twenty-first switch 341, the control terminal of the twenty-second switch 351, and the twentieth The control terminals of the three switches 361 are all connected to the display control timing or display touch control timing 152(i).

The second end of the twenty-fourth switch 371 is connected to the touch detection circuit 702.

Similarly, in this embodiment, each signal selection circuit 151(i) may correspond to one touch detection circuit 702, or multiple signal selection circuits 151(i) correspond to the same touch detection circuit 702, thus:

There are a plurality of touch detection circuits 702, each of the common traces COM(i) is connected to one of the signal selection circuits 151(i), and each of the signal selection circuits 151(i) is connected to any The touch detection circuit 702 is connected. Or, each of the common traces COM(i) is connected to one of the signal selection circuits 151(i), and a plurality of the signal selection circuits 151(i) are all connected to the same touch detection circuit 702.

Based on the above-mentioned embodiments, with reference to FIGS. 5-7, an embodiment of the present invention also provides a specific implementation structure of a reference voltage generating circuit (503 or 603), including a first resistor 11, a second resistor 12, and a third The resistor 13, the fourth resistor 14, the fifth resistor 15, and the first amplifier 21, the second amplifier 22, the third amplifier 23, and the fourth amplifier 24.

Specifically, the first terminal of the first resistor 11 serves as the output terminal of the first preset voltage V0.

The second terminal of the first resistor 11 is connected to the non-inverting input terminal of the first amplifier 21 and the first terminal of the second resistor 12, respectively. The inverting input terminal of the first amplifier 21 is connected to the first The output terminal of an amplifier 21 is connected and serves as the output terminal of the second preset voltage V1.

The second terminal of the second resistor 12 is connected to the non-inverting input terminal of the second amplifier 22 and the first terminal of the third resistor 13 respectively. The inverting input terminal of the second amplifier 22 is connected to the first The output terminals of the two amplifiers 22 are connected and serve as the output terminal of the third preset voltage V2.

The second terminal of the third resistor 13 is connected to the non-inverting input terminal of the third amplifier 23 and the first terminal of the fourth resistor 14 respectively. The inverting input terminal of the third amplifier 23 is The output terminals of the three amplifiers 23 are connected and serve as the output terminal of the fourth preset voltage V3.

The second terminal of the fourth resistor 14 is connected to the non-inverting input terminal of the fourth amplifier 24 and the first terminal of the fifth resistor 15 respectively. The inverting input terminal of the fourth amplifier 24 is connected to the The output terminals of the four amplifiers 24 are connected, and serve as the output terminal of the fifth preset voltage V4.

The resistor divider circuit formed by resistor 11, resistor 12, resistor 13, resistor 14, and resistor 15 can obtain the required voltage value, and then through operational amplifier 21, operational amplifier 22, operational amplifier 23, and operational amplifier 24 Can provide V0, V1, V2, V3, V4, V5 voltage.

Again, it should be noted that in the embodiments of the present invention, the circuit shown by 101 is located inside the chip, and the signal transmission trace 500 shown by 102 is located outside the chip (on the LCD screen); that is, the signal shown by 102 The transmission traces are connected to the pins of the chip, and the pins of the chip extend to the liquid crystal screen, and a trace pattern shown by 102 is formed on the liquid crystal screen. It can be understood that, in this embodiment, the signal transmission wiring shown in section 102 and the display driving circuit 501 are combined for description to facilitate explanation.

Specifically, an embodiment of the present invention also provides a specific implementation circuit of a touch detection circuit, where the touch detection circuit includes: an amplifier and a plurality of switches.

The amplifier is used to detect the change value of the self-capacitance of the common electrode and output a voltage signal corresponding to the change value of the self-capacitance.

Specifically, referring to FIG. 5, the touch detection circuit may include: a first capacitor 51, a second capacitor 52, a fifth amplifier 50, a twenty-fifth switch 60, a twenty-sixth switch 61, and a twenty-seventh switch 62 , 28th switch 63 and 29th switch 64.

Specifically, both ends of the twenty-fifth switch 60 and the first capacitor 51 are connected in parallel to the inverting input end and the output end of the fifth amplifier 50, and the output end of the fifth amplifier 50 serves as a The output terminal of the touch detection circuit 502 is described.

The inverting input terminal of the fifth amplifier 50 is connected to the signal selection circuit 131(i) through a twenty-sixth switch 61, and the signal selection circuit 131(i) is connected to the signal selection circuit through the twenty-seventh switch 62. The second capacitor 52 is connected.

The non-inverting input terminal of the fifth amplifier 50 is connected to the fifth preset voltage V4 through the twenty-eighth switch 63, and is connected to the second preset voltage V1 through the twenty-ninth switch 64.

Combining the above circuit structure, the working principle of this solution is now explained as follows:

In the display timing section, based on the display control timing, the display drive circuit is controlled to be in an on state, the touch detection circuit is controlled to be in an isolated and automatically corrected state, and a preset control voltage is gated to enable the display drive The circuit outputs a preset control voltage to the signal transmission trace.

Specifically, the first switch 31 may be controlled to be closed, so that the common trace COM(i) is connected to the sixth preset voltage V5, that is, the active common voltage at this time is V5, and the control The twenty-seventh switch 62 is closed, so that the second capacitor 52 stores a preset charge. The twenty-ninth switch 64 is controlled to be closed, so that the second preset voltage V1 is connected to the non-inverting input terminal of the fifth amplifier 50, so that the fifth amplifier 50 performs an automatic clearing operation.

In the display touch timing period, based on the display touch control timing, the touch detection circuit 502 is controlled to perform touch detection.

Specifically, the display touch timing segment includes a first stage and a second stage.

In the first stage, the display driving circuit 501 is in an on state, and the touch detection circuit 502 is in an isolated and self-correcting state. At this time, the inverting input terminal of the fifth amplifier 50 in the touch detection circuit 502 is connected to the output terminal, so that the output terminal of the fifth amplifier 50 is maintained at a specific voltage value, such as the second preset voltage V1.

In the second stage, the touch detection circuit 502 is in a detection state. At this time, the common voltage is connected to the inverting input terminal of the fifth amplifier 50. Due to the virtual ground effect during the normal operation of the fifth amplifier 50, the voltage at the inverting input terminal of the fifth amplifier 50 is the same as the voltage at the non-inverting input terminal. By connecting the non-inverting input of the fifth amplifier 50 to an appropriate potential, the potential on the common trace COM(i) can be maintained at the above-mentioned specific voltage value, such as the second preset voltage V1, at which time normal display can be maintained Function and can perform capacitance detection function.

Illustratively, the first switch 31, the second switch 32, the third switch 33, the fourth switch 34, the fifth switch 35, the sixth switch 36, the seventh switch 37 and the eighth switch 38 can be controlled to be off The twenty-fifth switch 60, the twenty-sixth switch 61, the twenty-seventh switch 62, and the twenty-ninth switch 64 are all closed, so that the touch detection circuit outputs a target voltage based on the touch action.

It can be seen that the touch display control circuit provided by this solution can enable the STN-LCD, TN-LCD, and CSTN-LCD liquid crystal screens to have a touch function without changing the structure of the original liquid crystal screen.

Based on the above embodiment, as shown in FIG. 8, this embodiment also provides an electronic device, including an electronic device body and any one of the above-mentioned touch display control circuits.

In summary, the present invention provides a touch display control circuit, a control method, and an electronic device. The control circuit is used to drive STN-LCD, TN-LCD, and CSTN-LCD liquid crystal screens, and includes a display drive circuit and a touch detection circuit. Among them, the display driving circuit includes a signal transmission trace, multiple sets of signal selection circuits and a reference voltage generation circuit. The signal transmission trace is used to transmit gate signals and common signals. The signal selection circuit selects based on display control timing or display touch control timing. With the preset control voltage, the reference voltage generating circuit provides the preset control voltage. The touch detection circuit is connected to multiple sets of signal selection circuits, and detects the touch signal to be tested based on the display touch control timing. It can be seen that the touch display control circuit provided by this solution can enable the LCD screen such as STN-LCD to have a touch function without changing the structure of the original LCD screen.

The embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments may refer to each other. The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown in this document, but should conform to the widest scope consistent with the principles and novel features disclosed in this document.

101‧‧‧ circuit 102‧‧‧circuit 11-15‧‧‧ First to fifth resistance 111 (i) ‧‧‧ switch group 112 (i) ‧‧‧ sequence 121 (j) ‧‧‧ switch group/gate signal selection sub-circuit 122（j）‧‧‧Display control sequence 131（i）‧‧‧ First circuit/signal selection circuit 132 (i) ‧‧‧ display touch control timing 151 (i) ‧‧‧ signal selection circuit 152 (i) ‧‧‧ display touch control timing 200‧‧‧Touch circuit 21-24‧‧‧ First to fourth amplifiers 31-38‧‧‧ First to eighth switches 31’-39’‧‧‧ switch from ninth to seventeenth 311‧‧‧Eighteenth switch 321‧‧‧19th switch 331‧‧‧20th switch 341‧‧‧21st switch 351‧‧‧22nd switch 361‧‧‧23rd switch 371‧‧‧24th switch 41‧‧‧Non-phase input 42‧‧‧Inverting input 500‧‧‧Signal transmission wiring 50‧‧‧ fifth amplifier 501‧‧‧Display drive circuit 502‧‧‧Touch detection circuit 503‧‧‧ Reference voltage generating circuit 504‧‧‧Common electrode signal selection sub-circuit 51‧‧‧ First capacitor 52‧‧‧Second capacitor 60-64‧‧‧ twenty-fifth to twenty-ninth switch 600‧‧‧Display drive circuit 601‧‧‧Common electrode signal selection sub-circuit 602‧‧‧Touch detection circuit 603‧‧‧Gate signal selection sub-circuit/reference voltage generating circuit 70‧‧‧Capacitance 702‧‧‧Touch detection circuit 71-73‧‧‧switch COM, COM (i) ‧‧‧ public wiring V0‧‧‧ First preset voltage V1‧‧‧ Second preset voltage V2‧‧‧The third preset voltage V3‧‧‧ Fourth preset voltage V4‧‧‧ fifth preset voltage V5‧‧‧ sixth preset voltage SEG, SEG (j) ‧‧‧ grid wiring

In order to more clearly explain the embodiments of the present invention or the technical solutions in the prior art, the drawings required in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are only In the embodiments of the invention, for those with ordinary knowledge in the technical field, without paying any creative labor, other drawings may be obtained according to the provided drawings. [FIG. 1] It is a driving waveform diagram for display on the STN-LCD liquid crystal screen in the prior art. [FIG. 2] A schematic diagram of waveforms drawing the waveforms in FIG. 1 together. [FIG. 3] It is a schematic diagram of the STN-LCD display driving circuit in the prior art. FIG. 4 is a schematic diagram of the driving principle of the touch circuit 200. 5 is a schematic diagram of a touch display control circuit provided by the present invention. 6 is another schematic diagram of a touch display control circuit provided by the present invention. 7 is another schematic diagram of a touch display control circuit provided by the present invention. [FIG. 8] A schematic structural diagram of an electronic device provided by this embodiment.

101‧‧‧ circuit

102‧‧‧circuit

11-15‧‧‧ First to fifth resistance

21-24‧‧‧ First to fourth amplifiers

121(j)‧‧‧Switch group/gate signal selection sub-circuit

122(j)‧‧‧Display control sequence

131(i)‧‧‧ First circuit/signal selection circuit

132(i)‧‧‧Display touch control timing

31-38‧‧‧ First to eighth switches

41‧‧‧Non-phase input

42‧‧‧Inverting input

50‧‧‧ fifth amplifier

51‧‧‧ First capacitor

52‧‧‧Second capacitor

500‧‧‧Signal transmission wiring

501‧‧‧Display drive circuit

502‧‧‧Touch detection circuit

503‧‧‧ Reference voltage generating circuit

504‧‧‧Common electrode signal selection sub-circuit

60-64‧‧‧ twenty-fifth to twenty-ninth switch

COM, COM(i)‧‧‧public wiring

V0‧‧‧ First preset voltage

V1‧‧‧ Second preset voltage

V2‧‧‧The third preset voltage

V3‧‧‧ Fourth preset voltage

V4‧‧‧ fifth preset voltage

V5‧‧‧ sixth preset voltage

SEG, SEG(j)‧‧‧‧Gate wiring

Claims (12)

A touch display control circuit is used to drive a liquid crystal screen. The touch display control circuit includes: A display driving circuit includes a signal transmission trace, a signal selection circuit, and a reference voltage generating circuit. The signal transmission trace is used to transmit a gate signal and a common signal. The signal selection circuit is based on a The display control timing or a display touch control timing selects a preset control voltage, the reference voltage generating circuit is connected to the signal selection circuit, and is used to provide the preset control voltage; and A touch detection circuit is connected to the signal selection circuit, and performs touch detection based on the display touch control timing. The touch display control circuit according to claim 1, wherein the signal selection circuit includes: A gate signal selection sub-circuit is connected to the reference voltage generating circuit, gates a target gate voltage based on the display control timing, and transmits the target gate voltage to a gate trace in the signal transmission trace ;as well as A common electrode signal selection sub-circuit, connected to the reference voltage generating circuit, gates a target common voltage based on the display control timing or the display touch control timing, and transmits the target common voltage to the signal transmission trace A public wiring. The touch display control circuit according to claim 2, wherein there are a plurality of touch detection circuits, each of the common traces is connected to one of the common electrode signal selection sub-circuits, and each of the common electrode signal selection sub-circuits is connected to Any one of the touch detection circuits is connected. The touch display control circuit according to claim 2, wherein each of the common traces is connected to the common electrode signal selection sub-circuit, and a plurality of the common electrode signal selection sub-circuits are all connected to the same touch detection circuit . The touch display control circuit according to claim 2, wherein the signal selection circuit includes a plurality of switches, and the control end of each switch is connected to the display control timing or the display touch control timing to gate the preset control The voltage is routed to the signal. The touch display control circuit according to claim 5, wherein there are a plurality of touch detection circuits, each of the common traces is connected to one of the signal selection circuits, and each of the signal selection circuits is connected to any one of the touch detection The circuit is connected. The touch display control circuit according to claim 5, wherein each of the common traces is connected to one of the signal selection circuits, and a plurality of the signal selection circuits are connected to the same touch detection circuit. The touch display control circuit according to claim 1, wherein the touch detection circuit includes: an amplifier and a plurality of switches; the amplifier is used to detect a change value of a self-capacitance of a common electrode, and the output and the self-capacitance A voltage signal corresponding to the changed value. A control method applied to the touch display control circuit according to claim 1, the control method includes: In a display timing segment, based on the display control timing, the display driving circuit is controlled to be in an on state, the touch detection circuit is controlled to be in an isolated state, and the preset control voltage is gated so that the display driving circuit outputs the preset Control voltage to the signal transmission trace; and In a display touch timing period, based on the display touch control timing, the touch detection circuit is controlled to perform touch detection. The method according to claim 9, wherein the display touch timing period includes a first stage and a second stage; In the first stage, the display driving circuit is in an on state, and the touch detection circuit is in an isolated and self-correcting state; and In the second stage, the touch detection circuit is in a detection state. The method according to claim 9, further comprising executing the display control timing and the display touch control timing according to a preset rule; The preset rule includes: the display control timing and the display touch control timing are executed alternately m times in succession; wherein, m is an integer greater than or equal to 0; and n is an integer greater than or equal to 1. An electronic device includes an electronic device body and the touch display control circuit according to any one of the request items 1-8.

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